Container for food product

ABSTRACT

A container for receiving a food product and folded from a blank, the container comprising a main body defining an opening for receiving the food product and a circumjacent flange ( 11 ), and the surface of the blank forming the inner surface of the container having a plastics coating such that a plastics film can be heat sealed to the flange to create a substantially airtight container for the food product.

[0001] This invention relates to a container for receiving a food product and in particular the invention is concerned with containers that can be formed by folding a shaped blank of paper, paperboard, cardboard or a similar material. (Reference in this specification to ‘paperboard’ are to be taken to include paper, cardboard and similar materials.)

[0002] Containers for food products such as sandwiches tend to be manufactured from paperboard or from plastics. Paperboard is generally preferred as it is recyclable and regarded as more environmentally friendly than the plastics alternative, but where food products are not packaged at the point of sale for immediate purchase, plastics containers are used to ensure product freshness is maintained for as long as possible by providing an airtight compartment for the food product. Further, the shelf life of food products in cardboard containers is limited as grease or fat from the food product permeates through the paperboard after a number of hours to discolour the paperboard.

[0003] However, there exists a desire to combine the environmental benefits of paperboard containers with the advantages that stem from the use of plastic containers.

[0004] With this desire in mind, the present invention provides a container for receiving a food product and folded from a blank, the container comprising a main body defining an opening for receiving the food product and a circumjacent flange, and the surface of the blank forming the inner surface of the container having a barrier coating such that a plastics film can be heat sealed to the flange to create a substantially airtight container for the food product.

[0005] The barrier coating allows the plastics film to be heat sealed to the flange, and it also serves to decrease the permeability of the paperboard and thus to improve the shelf life of the food product within the container. Similarly, the reduced permeability of the paperboard serves to slow the passage of grease or fat from the food product out of the container.

[0006] Advantageously, the barrier coating may also enable the blank to be secured in the form of the container by heat treatment of the main body. The uniform coating across the inner surface of the blank, and the use of heat treatment to secure the container in the assembled condition, ensures a uniform seal is obtained across the full width of all joints and thus helps to increase the integrity of the main body. In addition, the need for separate adhesive can be avoided.

[0007] Preferably, the main body of the container comprises a substantially rectangular rear portion with opposed pairs of major and minor sides, and pairs of side panels and end panels integrally connected to the rear portion at the minor and major opposed sides respectively, the side panels having side edges which extend at oblique angles to said minor opposed sides.

[0008] Preferably, the outmost edges of the side and end panels, which combine to define the opening of the container, each have an integral flange-forming portion. It is preferred that the flange-forming portions extend beyond the lateral extremity of the side and end panels, such that the flange defined by the flange-forming portions has a substantially uniform width.

[0009] Furthermore, the adjacent side edges of the side and end panels may be connected and sealed by a flap integrally formed with one of said side or end panel and extending substantially along the length of the side edge.

[0010] Although this embodiment is generally effective it has been found that fat or grease from the sandwich is absorbed by the paperboard in the region of the free edges of the flap and in some cases this can lead to the shelf life of the sandwich being reduced to less than 48 hours.

[0011] Therefore, in a preferred embodiment a webbing arrangement is provided between the side and end panels. The webbing arrangement is contiguous with the side and end panels and serves to minimise the area of the free edge which is exposed to fat or grease in the assembled container.

[0012] Preferably, a radiused cut is provided in the region of the intersection between the flap edge and the flange-forming portions. Further, the radiused cut is offset from the crease line. The two foregoing features, individually and collectively, improve the integrity (airtightness) of the main body to increase the shelf life of the food product.

[0013] Preferably, creasing, rather than scoring, the paperboard forms fold lines in the blank. Creasing is advantageous compared with scoring as it does not prejudice the integrity of the main body of the container, and this contributes to the decreased permeability of the container main body.

[0014] Similarly, it is preferred that cuts provided between the flaps and the side edges of the side panels in the region of the rear portion are terminated a distance short of the crease lines to increase the integrity of the main body in the vicinity of the rear portion and thus improve the shelf life of the food product.

[0015] The barrier coating is preferably selected from a group of thermoplastics such as polyethylene or a water based acrylic coating, such as TECTRA™ can be used.

[0016] It is preferred that the side and edge panels cooperate to define a substantially uniplanar opening to the container.

[0017] According to yet another aspect of the present invention there is provided a blank for forming a container as described above.

[0018] Further, according to yet another aspect of the present invention there is provided a container as described above having a plastic film sealed to the flange to form a substantially airtight compartment for the food product contained therein.

[0019] A clear understanding of the present invention will be gained from the following detailed description, given by way of example only, with reference to the accompanying drawings, in which:

[0020]FIG. 1 is a plan view of a container blank according to an aspect of the invention;

[0021]FIG. 2 is a first perspective view of a blank partially assembled into a container;

[0022]FIG. 3 is a second perspective view of a blank partially assembled into a container;

[0023]FIG. 4 is a perspective view of a container according to an aspect of the invention;

[0024]FIG. 5 is an enlarged view of a container of the blank shown in FIG. 1; and

[0025]FIG. 6 is a plan view of a container according to a preferred embodiment of the invention.

[0026] The container blank shown in FIG. 1 may consist of papers, paperboard, cardboard or a similar material. The surface of the blank that is used to form the inner surface of the containers is coated with a plastics coating such a polyethylene TECTRA™. The blank includes a generally rectangular central portion 1, with a minor pair of parallel sides 2 defined by fold lines and a major pair of parallel sides 2 defined by fold lines and a major pair of parallel sides 3, also defined by fold lines.

[0027] Integrally formed with the rear portion 1 along the fold lines 2 are side panels of essentially identical shape and attached to the rear panel along fold lines 3 are end panels 5, also of substantially identical shape. The outermost edges of the side and edge panels are defined by fold lines 6 and, as can be clearly seen from FIG. 4, the outermost edges of the side and end panels 6 are arranged to lie in a common plane and thus define a uniplanar opening to the main body of the container, generally designated 7.

[0028] Fold lines 8 delineate tabs or flaps 10 which extend along the length of the end panels 5. The flaps 10 are contiguous with the side panels 4 in the region of the rear portion 1, and cuts 9 separate the flaps form the side panels 4 in this area. The cuts 9 extend up to, but not through the folding lines 2 and 8 in the region of the rear portion 1.

[0029] Elongate rectangular flange-forming flaps 11 are integral with the side and end panels 4,5. The flange-forming flaps 11 are delineated from the side and end panels 4,5 by the fold lines 6. In relation to the end panels, fold lines 8 extend in the form of fold lines 12 onto the flange-forming portions to define substantially square end areas 13 of the flange-forming flaps 11. In relation to the side panels, the flange-forming flaps 11 extend at each end beyond the extremity of the side panels 4. The extended sections of the flange forming flaps are substantially identical in size and shape to the square end areas 13 of the adjacent flange-forming flaps.

[0030] With reference to FIG. 5, a radiused cut 15 is provided at the intersection of the flap 10 and the end area 13 of the flange-forming flap 13. The radiused cut 15 is set away from the fold lines 8 and 12 by a small distance such that it does not interfere with the folding of the blank in this region. Thus, the integrity of the seal formed between the abutting flange-forming flaps 13 when the container is assembled is not prejudiced and the shelf life of the food product is increased.

[0031] The webbing arrangement, generally designated 20, has two flaps or tabs 20 a and 20 b that are integrally formed with the end and side panels 5,4. The flaps 20 a,b share a common contiguous edge which defines a fold line 21 radiating out from the intersection between the rear portion 1 and the side and end panels 4,5. The fold line 21 is configured to fold in the opposite direction to the neighbouring fold lines. To aid the folding process the fold line 21 terminates a distance from the outermost edge of the webbing arrangement 20, with the remainder of the flaps 20 a,b defining free edges 22 a,b respectively.

[0032] In the assembled container the flap 20 a overlies the flap 20 b to sandwich the flap 20 a between the flap 20 b and the side panel 4. Thus, the area of the free edge of the webbing arrangement that might be susceptible to the ingress of grease or fat is reduced. Further no free edge is exposed in the region of the rear portion 1 of the container where grease or fat is most likely to collect.

[0033] The skilled man will understand the modifications or developments to the modified construction are possible without departing from the scope of the invention. For instance, the shape of the tabs 20 a,b shown in the drawings illustrates a preferred configuration, but should not be regarded as limiting as other configurations which reduce the area of the free edge of the webbing arrangement that might be exposed to grease of fat may be viable.

[0034] Although the blank can be cut to shape and provided with fold lines according to conventional manufacturing techniques, it is important to note that the fold lines are creased, rather than scored, to avoid weakening the integrity of the assembled container.

[0035] With reference to FIGS. 2 and 3, the blank is assembled such that the flaps 10 line internally of the side panels 4. The square end areas 13 of the flange-forming flaps 11 associated with the end panels 5 overlie the extended end portions of the flange-forming flaps associated with the side panels 4, and the container is sealed in the configuration shown in FIG. 4 by the reaction of the barrier coating to the application of heat and pressure around the main body 7 of the container. It is preferred to sandwich the container between a shaped male and female member, with heat being applied through the male and female member to seal the abutting parts of the blank and thus form the container.

[0036] The front or upper surface of the flange defined by the flange-forming flaps 11 presents the barrier coated surface. Once a sandwich or other food product is placed within the container main body 7, a film of plastics can be heat sealed to the presented surface of the flange to provide, with the main body, a substantially airtight compartment for the food product. The plastics film is preferably clear to allow the contents of the container to be inspected by the consumer.

[0037] A container formed in this manner has been shown to keep a sandwich fresh for between 48 to 72 hours or longer from the application of the plastic film. Further, the plastics coating on the cardboard serves as a barrier layer to prevent grease or fat from the sandwich discolouring or damaging the main body. In addition, the barrier layer reduces the permeability of the main body to improve the shelf life of the food product.

[0038] The rear portion 1 of the blank allows a satisfactory seal to be obtained at the rear of the container, although it represents a compromise on the deal shaping of the container which would come to a point at the rear to maximise the inner volume of the main body. Nevertheless, by keeping the minor sides 2 of the rear portion smaller than the major sides 3 a satisfactory seal can be obtained without unduly compromising the volume of the container body. 

1. A container for receiving a food product and folded from a blank, the container comprising a main body defining an opening for receiving the food product and a circumjacent flange, and the surface of the blank forming the inner surface of the container having a barrier coating such that a plastics film can be heat sealed to the flange to create a substantially airtight container for the food product.
 2. A container according to claim 1, wherein the main body of the container comprises a substantially rectangular rear portion with opposed pairs of major and minor sides, and pairs of side panels and end panels are integrally connected to the rear portion at the minor and major opposed sides respectively, the side panels having side edges which extend at oblique angles to said minor opposed sides.
 3. A container according to claim 2, wherein a webbing arrangement is provided between the side and end panels.
 4. A container according to claim 3, wherein the webbing arrangement is contiguous with the side and end panels.
 5. A container according to claim 2, wherein the adjacent side edges of the side and end panels are connected and sealed by a flap integrally formed with one of said side or end panel and extending substantially along the length of the side edge.
 6. A container according to claim 2, wherein the outermost edges of the side and end panels, which combine to define the opening of the container, each have an integral flange-forming portion.
 7. A container according to claim 6, wherein the flange-forming portions extend beyond the lateral extremity of the side and end panels, such that the flange defined by the flange-forming portions has a substantially uniform width.
 8. A container according to claim 6, wherein a radiused cut is provided in the region of the intersection between the flap edge and the flange-forming portions.
 9. A container according to claim 1, wherein the paperboard fold lines are defined by creases in the blank.
 10. A container according to claim 1, wherein cuts provided between the flaps and the side edges of the side panels in the region of the rear portion are terminated a distance short of the crease lines.
 11. A container according to claim 1, wherein the barrier coating is selected from a group of thermoplastics, such as polyethylene.
 12. A container according to claim 1, wherein the barrier coating is a water based acrylic.
 13. A container as described in claim 1 having a plastics film sealed to the flange to form a substantially airtight compartment for a food product contained therein.
 14. A blank for forming a container as defined in claim
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